Variable-compression internal-combustion engine



April 15, 1930. s. s. ALLWILL VARIABLE COMPRESSION INTERNAL COMBUSTION ENGINE Filed April 23, 1928 3 SheetsSheec 1 Q INVENTOIZ 5.6.u7llwill, M

' atto'cwzq April 15, 1930. s. s, ALLWlLL VARIABLE COMPRESSION INTERNAL COMBUSTION ENGINE 5 Sheets-Sheet 2 Filed April 25, 1928 gwm'n-io'r; 5.5.u7llwill,

7 April 15, 1930. s. s. ALLWlLL VARIABLE COMPRESSION INTERNAL COMBUSTION ENGINE Filed April 25, 1928 3 Sheets-Sheet Patented Apr. 15, 1930 UNITED STATES PATENT OFFICE STEPHEN SEYMOUR ALLWILL, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO ROBERT LEE GRAY, OF WASHINGTON, DISTRICT OF COLUMBIA VARIABLE-COMPRESSION INTERNAL-COMBUSTION ENGINE Application filed April 23,

This invention has been devised in order to provide improvements in the construction 7 of internal combustion engines, by the adoption of which, provision is made for the degree of compression of the explosive charges being automatically maintained at a constant, no matter What the volume of the charges drawn into the engine may be.

- With these engines as at present constructed, the cubical area of the compression chamber in each cylinder remains the same throughout, so that when the throttle is fully open and full charges are being drawn into such chamber, and the engine is running at full speed, the degree of compression of each charge reaches its maximum, while when the throttle is partially closed and the charges drawn in are correspondingly reduced, the

degree of compression also is reduced. Thus the resultant power obtained by the expansion of the gases on each explosion is not as great as it should be, when running at slow speed, proportionately to the power obtained when running at high speeds, simply because the lessened degree of compression provides less expansive force on explosion.

The present invention has been devised with the object of overcoming this drawback and to provide that equal compression may be obtained automatically upon all variations of the charges, that is, a small charge will receive compression to the' same degree as a large charge, and thus better power results are obtained. s

The invention provides for this degree of compression being fixed to accord with the nature of the oil fuel employed, as it is well known that the different grades of fuel give ,best results when-their resultant gases are compressed to certain degrees of compression. Thus for benzine, one degree of compression may be fixed asthe constant, for alcohol, another, and so on.

The invention may be carried out by providing each engine cylinder with .a movable head or floating piston arranged to move vertically within the cylinder, with relation to the travel of the piston, soas to vary the area of the space between the piston and such head, and the head is moved mechanically re- 1928. Serial No. 272,288.

of the gear ring mounted on the floating, piston which is provided with teeth and grooves meshing with corresponding teeth and grooves on the floating piston and the worm gear on the piston forms a mechanical lockagainst movement except when rotated by the auxiliary operating piston by means of a worm gear meshing with the worm gear on the floating piston. Further objects reside in the fluid pressure control and the cam construction for the intake and exhaust valves as well as the construction of the ports in the floating piston themselves.

Still further objects will be apparent from the'following description taken in connection with the accompanying drawings in which like reference characters indicate corresponding parts throughout and in which:

Figure 1 is a longitudinal section of a four cylinder-four cycle engine,

Fig. 2 is a section at right angles to the section of Fig. 1 through cylinder 4 of the engine,

Fig. 3 is a top view of the worm gear ring of the floating piston,

Fig. 4 is a side view of the floating piston,

Fig. 5 is a bottom view of the floating piston,

Fig. 6 is a section through the worm gear rm 9 B ig. 7 is a side view of the pair of gears and control shaft for the floating piston,

Fig. 8 is a section through a cylinder of a sleeve valve motor,

Fig. 9 is a section through the stationary head of the cylinder of Fig. 8,

Fig. is .a side view of the floating piston of the cylinder of Fig. 8,

Figi. 11 is a top view of the cylinder of Fig. 8, an

Fig. 12 is a section through the cylinder of a modified motor construction.

The engine according to Figs. 1 to 7 comprises four cylinders 1, 2, 3 and 4, each havmg a piston 5 therein and surrounded by a casing' lo comprising a water jacket 50. In the upper part 6 of each cylinder, which is referably of a reater diameter than the ow.er part, a floatlng piston or head 11 is provided which is grooved to provide teeth 12 on the upper part and grooves 13 on the lower ,art to receive the usual sealing rings 47. er the teeth 12, a worm gear ring fits which is provided with corresponding inner teeth 14 which mesh in the grooves formed by the teeth 12 in the piston. The outside of the ring 15 is provided with a worm gear 65 cut in its periphery and this ring is. adapted to rotate in the upper part 90 of the cylinder which is above and is of a greater diameter than ortion 6. The-ring 15 is rotatably retaine in the portion 90 by means of a retaining plate 33 which is bolted down on the linder by bolts 34. The floating piston des vertically in the portion 6 of the cylinder, when the ring 15 is rotated, and it is prevented from rotating b a key and slot arrangement, theke 96 being secured in the cylinder and the s 0t 66 in the piston. The piston therefore slides on the keyby means of its slot.

Each floating piston 11 has a pair of openings 91 therein preferably on opposite sides and the interior of the piston is divided into two parts'by means of partition 92 so that each part has one opening 91 therein. Also each part ofthe piston has a valve therein of which 19 is the exhaust valve and 23 the intake valve for the fuel. These valves seat in openin 97 in the bottom of the floating iston. For the purpose of conveying the uel and exhaust gases, an exhaust manifold and an intake manifold 43 is provided in the part 6 of the casing 10 and these manifolds cooperate with-the respective .openin 91 in the piston.

he valves 19 and23 are spring pressed to urge them on their seats at all times and such springs 46 are preferabl mounted in a recess 24 on the top of the eating pistons andbear thereagainst. These valves are operated by cams 28 mounted on a common cam shaft 27 constructed in sections and connected together in spaced relation by flexible couplings 30. This cam shaft is mounted in ball bearings 29 mounted in extensions 31 on and preferably integral with the floating pistons. As thefloating pistons move vertically approximately u wardl and downwardly togethegthe entire sha t 27, cams 28' and bearmgs 29 move likewise and the couplings 30 allow for any slight movement of a single floating piston irres ective of the others. At one end of the she. a bevel gear 38 is secured which meshes with a bevel gear 39 mounted on connecting shaft 40. This shaft 40 is slidably mounted in supports 42 and has a square cross-section at the lower end 32 which slidably fits into a corresponding section 41 of a drive shaft 98. The bevel gears 38 and 39 are maintained in mesh by the retaining member 36 which has thrust bearings 44 therein. The shaft 40 therefore rises and falls with the cam shaft but motion is alwaysimparted to the cam shaft due to the coupling 32 and 41, that is, the square end 32 sliding in the corresponding member 41.

Each cylinder 1 to 4 is provided with a spark plug 9 preferably provided in portion 6 of the cylinder wall. Also each cylinder may comprise an actuator or regulator for the floating piston or a single actuator can be used for all of the floating pistons which includes a double piston rod 53 having a piston 56 and 57 at each end and sliding in a cylinder 25. At the lower end of this cylinder a valve mechanism 61 rotates in a casing 26 and the valve and casing are preferably circular but other types of valves can be used. The casing 26 communicates with the interior of the cylinder 4 to which it is secured by means of pipe 60 and opens into the cylinder 25 by means of an opening 72 in the casing 26. The

valve is operated by a lever 62 having a slot 87 in the outer endthereof in which a rod 63 is adjustably secured and this rod 63 is suitably operated by the engine by an eccentric mechanism 101. The slot 87 permits for the regulation of the operation of the valve and this is preferably carried out automatically by a speed responsive device 83 mounted on a shaft 86 and operated by the engine by means of pulley 85. The rod 63 slides in an abutment 82 of the speed responsive device and by shifting this a utment on the shaft .86 the rod 63 will also be shifted. The casing 26 has a further opening'73 which by means of a suitable pipe communicates with the intake manifold of the carbureter, not shown, which is for the purpose of returning the gases used to actuate the piston rod 53 for re-use.

The piston rod 53 is provided with a plurality of teeth 64 which are adapted to mesh with the gear 52 which in turn operates the shaft 45, worm gear 51, worm gear ring 15 and finally the res ective floating piston or pistons 11. The plston rod 53 may be actuated b fluid pressure entering through pipe 59 an acting on piston 56 or a sprlng 55 or both can be used, the latter also acting on the piston 56. The spring 55 may be ad usted by means ofan ad usting plate 98 having a screwthreaded spindle 99 and a nut head 100 for effecting ad]ustment.

Fig. 8 shows a sleeve-valve motor which,

comprises the usual sleeves 76 and 77, one within the other and both reciprocating in a cylinder which is surrounded by a water jacket 50. The sleeves are actuated in the usual manner and the upper part of the cylinder comprises a block 67 between which and the cylinder wall the upper parts of the sleeves pro ect. This block has internal grooves and teeth 71 which are adapted to mesh with corresponding grooves and teeth 93 of the floatlng piston 11. The lower end of the floating piston has a piston or sealing ring 47 in a suitable groove and in the center a spark plug 9 is inserted. The block 67 also has a ring 81 therein to form a tight seal between it and the sleeve 77. At the top of the floating piston and on the block 67, the gear ring 15 is provided which imparts rotation to the floatmg piston by the pin 68 mounted therein and projecting into the groove 94in the piston 11. The gear ring 15 is operated by the same" means as in the construction of Figs. 1 and 2 and is held in place by a plate 33 and bolts 34 which also extend through the holes 95 in the block 67 and into the engine casing, to thereby securethe plate 33 andthe block 67 on the cylinder. In this sleeve valve motor the floating piston rotates as it is adjusted vertically. The control for the piston is the same as in the construction of Figs. 1 and 2 and the passage 60 leading to the control de vice projects through'the block 67 and the sleeves.

The modification according to Fig. 12

- shows a side valve engine having the spark plug 9 and the valve 70 at the side of the cylinder. The floating piston 11 is actuated by the usual gear ring and grooves and teeth as shown and operating in a manner similar to' the construction of Figs. 8 to 11. f

The most important features of applicants invention may be outlined as follows: Constant compression is obtained under all conditions irrespective of the speed of the engine. Increased compression takes place on top center before explosion. The adjustable heads or floating pistons follow the power piston during a part of the explosion stroke but are securely lockei against upward movement during. explosion stroke.

Regarding the increased compression taking place on top center before explosion, 1t

is explained that, if desired, the valve 61 can be operated to close the pipe 60 and open to pipe 7 3 before extreme top dead center is reached. This will} result in the pressure on the piston 56 forcing the rod 53 downwardly to also force the floating piston downwardly thereby adding to the pressure of the compressed fuelto increase the efficiency. The operation of the engine is as follows When the piston 5 of cylinder 4: is coming up on compression stroke the valve 61 has opened the connection between pipe 60 and opening 72 to allow the pressure in the cyl1n'- der 4 to be communicated into the space 54 of the cylinder 25. On the top of the piston 56 1s a pressure of, for instance, 100 lbs. which is supplied either by means of a spring or. compressed air or both. Assuming the floating piston 11 and the pistons 56 and 57 to be in their lowest position, these members will not be moved or adjusted so long as the pressure of the fuel being compressed remains under 100 lbs. As soon as a pressure slightly great-- er than 100 lbs. of the fuel is reached the pistons 56 and 57 together with rod 53 will move upwards, thereby actuating the gear 52, shaft 45, worm gear 51, and worm gear ring 15. Rotation of the latter causes the floating piston to rise, due to the teeth and grooves-12 and 14, until the piston 5 has reached top center,

whereupon the valve 61 will close the pipe 60 l to prevent any further upward movement of the floating piston. The valve 61, however, immediately opens opening 72 to the pipe 73 which is connected to the intake manifold, thereby releasing the pressure in the lower part of the cylinder 25 to allow the spring or pressure onpiston 56 to actuate the floating piston downwardly when the pressure in the power cylinder falls during and after the firing stroke. The floating piston will be moved to its lowest position, and is in that position prepared for another compression stroke.

Any degree of compression can be used and one can be altered to another by simply altering the pressure on the piston 56 or by altering the tension of spring 55, or both, mainly well known fact that a motor operating at high speed requires a higher compression to obtain the best results. As the engine speed increases the governor will cause the valve 61 to close at a period just before top center of piston 5.to thereby render a higher compression ratio than the fixed ratio. As the engine speed decreases the governor will cause the. valve to close as the piston 5 reaches top center and thereby reduce the compression to the set amount. By the use of the double com pression principle, the. compression can be maintained until the crank has passed over the top center, so that the full force of the explosion will be delivered to the crank shaft when it is in the most efficient position, which is just past top dead center.

In a multi-cylinder engine, one cylinder 25 can control allof the floating pistons. In this case the valve 61 will only be open on the compression stroke of the cylinder on which it is secured and thereby adjust all of the floating pistons in the engine. In such a construction, the floating pistons will remain practically stationary one they have been adjusted and will only slightly move vertically in response to change of speed when possibly more or less fuel is drawn into the cylinder and therefore an ad'ustment of the compression is necessary. uch an arrangement excludes the connection 62 since the pressure of the fuel in the cylinder 25 is not relieved at any time but remains practically at the constant set for the specific fuel used. The valve 61 is, of course, closed during firing, exhaust and intake stroke and is open only during a part of the compression stroke, that is, during only the latter part of the compression stroke.

A manual control can be provided for the shaft 45 so that in case of uniform load and s eed of the engine, one setting would be sufficient. In that case, the valve 61 should be disconnected in closed position. Also in case the valve or control mechanism should become inoperative for any reason, such as a breakdown, the manual control will provide for the setting of the engine so that its proper operation may be continued.

In the engine of Figs. 1 and 2, the spark plug may be inserted in the floating piston instead of in the cylinder wall.

I claim as my invention:

1. A variable compression internal combustion engine comprising a cylinder; a power iston in said cylinder; a floating piston sli ably mounted in the upper part of the cylinder and having teeth and grooves therein;

means provided around said floating piston having teeth and grooves meshing with the teeth and grooves of the floating piston; and means for automatically actuating said firstnan ed means to provide an approximate constant pressure for the compressed fuel charge.

2. A variable compression internal combustion engine comprising a cylinder; a power piston in said cylinder; a floating piston slidably mounted in the upper part of the cylinder and having teeth and grooves therein; a worm gear ring provided around said floating piston and having teeth and grooves therein meshing with the teeth and grooves of the floating piston; and means for actuating said gear ring to adjust the floating piston in the cylinder to provide an approximate constant pressure for the compressed fuel charge.

3. A variable compression internal combustion engine comprising a cylinder; a power piston in said cylinder; a floating piston slidably mounted in the upper part of the cylinder and having teeth and grooves; a worm gear ring provided around said floating piston and having teeth and grooves therein meshing with the teeth and grooves of the floating piston; means for actuating said gear ring .to adjust the floating piston in the cylinder to providean approximate constant pressure for the compressed fuel charge; and

an intake valve and an exhaust valve mounted in said floating piston.

4. A variable compression internal combustion engine comprising a cylinder; a power piston in said cylinder; a floating piston slidably mounted in the upper part of the cylinder and having teeth and grooves; a worm gear ring provided around said floating piston and having teeth and grooves therein meshing with the teeth and grooves of the floating piston; means for actuating said gear ring to adjust the floating piston in the cylinder to provide an approximate constant pressure for the compressed fuel charge; an intake valve and an exhaust valve mounted in said floating piston and being spring pressed; and a cam shaft mounted in ball hearings on said floating piston and having cams thereon adapted toactuate said valves.

5. A variable compression internal combustion engine comprising a cylinder; 3. power piston in said cylinder; a floating piston slidably mounted in the.upper part of the cylinder and having teeth and grooves; a worm gear ring provided around said floating piston and having teeth and grooves therein meshing with the teeth and grooves of the floating piston; means for actuating said gear ring to adjust the floating piston in the cylinder to provide an approximate constant pressure for the compressed fuel charge; an intake valve and an exhaust valve mounted in said floating piston and being spring pressed; a cam shaftmounted in ball bearings on said floating piston and having cams thereon adapted to actuate said valves; and means for rotating said cam shaft.

6. A variable compression internal combustion engine comprising a cylinder; a power piston in said cylinder; 3. floating piston slidably mounted in the upper part of said cylinder and having teeth and grooves therein; a gear ring provided around said floating piston having two sets of teeth and grooves therein, one set being on the inside of the ring which mesh with the teeth and grooves of the floating piston; and means cooperating with the other set of teeth and grooves in the gear ring for automatically actuating said ring to adjust the floating piston in the cylinder to provide an approximate constant pressure of the compressed fuel charge.

7. A variable compression internal combustion engine comprising-acylinder; a power piston insaid cylinder; a floating piston slidably mounted in the upper part of said cylinder andhaving teeth and grooves therein; a gear ring provided around said floating piston having two sets of teeth and rooves therein, one set being on the inside of t e ring which mesh with the teeth and grooves of the floating piston; a shaft having a worm gear thereon meshing with the other set of teeth and grooves of the ring; a second gear mounted on said shaft; and means cooperating with said second gear for automatically actuating said ring to adjust the floating piston in the cylinder to provide an approxim ate. constant floating piston; a shaft having a Worm gear thereon meshing with the other set of ,teeth and grooves of the ring; a second gear mounted on said shaft; a piston and rod mounted in an auxiliary cylinder, said rod having teeth thereon meshing with the gear; and a valve communicating with the interior of the cylinders adapted to automatically control the piston and rod to adjust the floating piston in the cylinder to provide an approximate constant pressure of the compressed fuel charge.

9. A variable compression internal combustion engine comprising a cylinder; a power piston in said cylinder; a floating piston slidably mounted in the upper part of said cylinder and having teeth and grooves therein; a gear ring provided around said floating piston having two sets of teeth and grooves therein, one set being on the inside of the ring which mesh with the teeth and grooves of the floating piston; a shaft having a worm gearthereon meshing with the other. set of teeth and grooves of the ring; a second gear mounts ed on said shaft; a plston and rod mounted in an auxiliary cylinder, said rod having teeth thereon meshing with the gear; a valve communicating with the interior of the cylinders adapted to automatically control the piston and rod to adjust the floating piston in the cylinder to provide an approximate constant pressure of the compressed fuel charges; and

means for operating said valve including a speed responsive device for adjusting the constant degree of compression at different speeds of the engine. p

10. A variable compression internal combustion engine comprising a cylinder; a power piston in said cylinder; a floating piston mounted in the upper part of the cylinder; aring mounted around and adapted to actuate said floating piston; and means for automatically actuating said ring to provide an approximate constant pressure for the compressed fuel charge.

11. A variable compression internal combustion engine comprising a cylinder; a power piston in said cylinder; a floating piston mounted in the upper part of the cylinder; a ring mounted around and adapted to actuate said floating piston; means for automat'ically actuating said ring to provide an approximate constant pressure for the compressed fuel charge; and means for retaining said ring in place.

12. A variable compression internal combustion engine comprising a cylinder; a

power piston in said cylinder; a floating iston mounted in the upper part of the cy inder and having two openings in the bottom thereof, two openings in the side thereof and a partition therein; an intake valve mounted in the floating piston on one side of the partition and seating in one of the bottom openings and cooperating with one of the side openings; an exhaust valve mounted in the floating piston on the othervside of the partition and seating in the other of said bottom openings and cooperating withthe other ofsaid side openings; a gear ring mounted around said floating piston'; and means for automatically actuating said ring to adjust the floating piston in the cylinder thereby providing an approximate constant pressure for the compressed fuel charge.

13. A'variable compression internal combustion engine comprising a cylinder; a power piston in said cylinder; a floating piston mounted in the upper part of the cylinder and having two openings in the bottom thereof, two openings in the side thereof and a partition therein; an intake valve mounted in the floating piston on one side of the partition and seating in one of the bottom openings and cooperating with one of the side openings; an exhaust valve mounted in the floating piston on the other side of the partition and seating in the other of said bottom openings and cooperating with the other of said side openings; a gear ring mounted around said floating piston; means for automatically actuating said ring to adjust the floating piston in the cylinder thereby providing an approximate constant pressure for the compressed fuel charge; and a cam shaft for actuating said valves.

14. controlling device for a variable compression internal combustion engine comprising an auxiliary cylinder secured to the engine; a piston and rod in said cylinder and having teeth in the rod thereof; means for applying a constant pressure on the piston depending upon the specific fuel used in the engine; a valve for communicating the pressure of compression of the fuel inthe engine to the piston; and means associated with the teeth of the-{piston rod for conveying the means for applying a constant pressure on th m the engine; a valve for piston depending upon the specific fuel used eriodically communicating the pressure of compression of the fuel in the engine to the piston and rod; and means associated with the piston rod for conveying the movement of the piston rod to the engine for specific adjustment to maintain an approximate constant pressure for the compressed fuel charge.

16. A variable compression internal combustion engine comprising a cylinder; a

cylinder and having teeth and rooves therein adapted to mesh with the teet and grooves of the cylinder; a ring mountedpn the top of said cylinder and around said floating iston, said ring and floating iston being a apted to rotate together and t e floating piston being slidably mounted in the ring; means for retaining said ring on the piston; and means for actuating said ring to adjust the floating piston in the cylinder to provide an approximate constant pressure for the compressed .power piston in said cylinder; a floating pisfuel charge.

ton slidably mounted in the upper part of said cylinder and having teeth and grooves in the side thereof; a gear ring provided around said floating piston and having inner and outer sets of teeth and grooves therein, the inner set meshing with the teeth and grooves of the floating piston; means for re"- taining said gear ring on the floating piston; and meansassociated with said outer set of teeth of the ring for automatically actuating said gear ring to adjust the floating piston in the cylinder to rovide an approximate constant pressure fhr the compressed fuel charge.

17. A variable compression internal combustion engine comprising a cylinder; a pair I of sleeve valves adapted to reciprocate in said cylinder; a block mounted on the to of said cylinder and projecting into the cylmder between which and the cylinder the upper part of the sleeves reciprocate and having teeth and grooves on the inner side; a fioatin piston mounted to move vertically in said Block and having teeth and grooves meshing with the teeth and grooves of the block; a rin mounted around and adapted to rotate sai floating piston; and means for actuating said ring to adjust the floating piston in the cylinder to fprovide an approximate, constant pressure orthe compressed fuel char e.

18. A variable compression interna combustion engine comprising a cylinder; a pair' of sleeve valves adapted to reci rocate in said cylinder; a block mounted on t e to of said In testimony whereof I aflix my signature. STEPHEN SEYMOUR ALLWILL.

cylinder and projecting into the cyllnder between which and the cylinder the upper part of the sleeves reci rocate and havm teeth and grooves on t e inner side; a oatin piston -mounted to'move vertically in sai lock and having teeth and grooves meshing with the teeth and rin mounted aroun and adapted to rotate sai floating piston; means for actuating said ring to adjust the floating piston in the cylinder to provide-Z an approximate constant A pressure for the compressed fuel char e; and

means for retaining said ring on sai block.

19. A variable compression internal combustion enginecomprising a cylinder having teeth and grooves in the upper part; a valve provided at the side of the cylinder; a power piston in said cylinder; a floatin piston mounted to rotate and move vertic y'in said rooves of the block; a v 

